OpenEuphoria

Re: submarine commander project

• Posted by don cole <doncole at pacbell??et> Dec 10, 2007
• 521 views

David Money wrote:
[snip]
> 
> I would include the conversions in the functions, so you could use your
> 0~3600 angle directly.  Something like this:
> 
> <code>
> constant PI=3.1415926535893238 --or include misc.e
> 
> function p2xy(atom r,atom sec)
> --r is distance, sec is angle (seconds after hour, measured from 12 o'clock)
>     atom a
>     a=sec*PI/1800 --convert to radians
>     return {r*sin(a),-r*cos(a)}
> end function
> 
> function vector(sequence pt1,sequence pt2)
> --distance and angle from pt1 to pt2
>     integer dx,dy
>     atom r,a
>     dx=floor(pt2[1]-pt1[1])
>     dy=floor(pt2[2]-pt1[2])
>     r=sqrt(dx*dx+dy*dy)
>     if r=0 then
> 	return {0,0}
>     end if
>     if dy<0 then
> 	if dx<0 then
> 	    a=2*PI-arctan(dx/dy)
> 	else
> 	    a=-arctan(dx/dy)
> 	end if
>     elsif dy>0 then
> 	a=PI-arctan(dx/dy)
>     else --dy=0 (one point above the other); can't use arctan formula
> 	if dx<0 then
> 	    a=3*PI/2
> 	else
> 	    a=PI/2
> 	end if
>     end if
>     return {r,1800*a/PI} --convert radians to decidegrees
> end function
> </code>
> 
>   The arctan function just works for -pi/2 to pi/2, so you have to figure
> out which quadrant you are in, and offset it.  Also, you have to avoid
> dividing by zero.  If r=0, the points are the same; the function will return
> 0 for the angle, too, but it's really undefined.
>   You had two minus signs in your function--was that a typo?  That would work
> for conventional angle measurements (counterclockwise), but it would make
> your clock run backwards.
> --David

  Thank you David for responding,

That sould about do it. I'll try it soon.

That was not a typo I got it from chessclock in the archives.

I corrected the problem with:

for x=3600 to 1 by -1 do

Don Cole